1. Field of the Invention
The present invention relates to a light emitting and/or detecting device and a method of manufacturing the same, and more particularly, to a light emitting and/or detecting device that has a quantum structure and a microcavity formed by diffusion of dopant and oxidation of substrate surface, and a method of manufacturing the same.
2. Description of the Related Art
A logic element, a computing element, and a drive element can be integrated with high density and high reliability on a silicon substrate because silicon is cheap and the integration procedure to materialize a high integrated circuit is much cheaper than that for a compound semiconductor. Thus, most integrated circuits use silicon (Si) as a base material.
Numerous research studies are being carried out on the possibility to manufacture silicon-based light emitting diodes to embody low-priced photoelectron devices. It is experimentally proved that porous silicon and nano-crystal silicon have good light emitting characteristics and research on using these material for the above purposes is currently in progress.
FIG. 1 is a cross-section of a conventional light emitting and detecting device as illustrated in International Publication No. WO 03/067670. Referring to FIG. 1, a conventional light emitting and/or detecting device includes a substrate 11, a doping layer 15 formed on one surface of the substrate 11, and first and second electrodes 17 and 19, respectively, which are electrically connected on the doping layer 15 and formed on the substrate 11. When the doping layer 15 is formed, it is formed using a mask, and a control layer 13 that makes the doping layer 15 ultra-shallow can be further included on one surface of the substrate 11. After the doping layer 15 is formed, the control layer 13 can be selectively removed. The substrate 11 is made of a predetermined amount of semiconductor materials including silicon (Si), for example, Si, SiC, or diamond, and is doped with an n-type dopant or a p-type dopant.
The doping layer 15 is doped with an opposite dopant type to the substrate 11 by injecting a predetermined amount of dopant, for example, boron or phosphorous, to the substrate 11 through an opening of the control layer 13. Meanwhile, the boarder of the doping layer 15 and the substrate 11, i.e. a p-n junction 14, is formed as a quantum well, and in order to show a photoelectric conversion effect by a quantum restriction effect, the doping layer 15 is doped to a wanted ultra-shallow depth. The depth of the doping layer 15 in an ideal light emitting and detecting device is in the range of tens of nanometers.
In order to form the doping layer 15 with such doping depth, an ion implantation process is normally used. Thereafter, a heat treatment process is carried out to induce recrystallization, and to make the dopant injected at this stage diffuse deeply within the substrate 11 to control the doping depth. However, it is difficult to control the doping depth.
To solve the above-mentioned problem, a method of diffusing a dopant into the inner substrate is used in which a thin layer that includes the dopant or the dopant as a thin layer is mounted on a substrate and then a heat treatment is carried out. Layers such as a boro-silicate glass (BSG) layer, a boron silicide or a boron layer can be used as the thin layer. However, in this case, the dopant (boron) is quickly diffused into the substrate to a depth more than 100 nm during the heat treatment process. Even in a ten-minute heat treatment, the dopant is diffused into the substrate to a depth more than 300 nm. Therefore, it is hard to control the speed of the diffusion of a dopant even in a process of manufacturing a light emitting and detecting device by using a diffusion layer.